Aeronautics. a maneuver executed by an airplane in such a manner that the airplane describes a closed curve in a vertical plane.

6.

a circular area at the end of a trolley line, railroad line, etc., where cars turn around.

7.

an arm of a cloverleaf where traffic may turn off or onto a main road or highway.

8.

Physics. the part of a vibrating string, column of air or other medium, etc., between two adjacent nodes.

9.

Electricity. a closed electric or magnetic circuit.

10.

Computers. the reiteration of a set of instructions in a routine or program.

11.

a wire, usually of platinum, one end of which is curved to form a loop, used for transferring microorganisms from one medium to another.

12.

a sand bar that encloses or nearly encloses a body of water.

13.

Figure Skating. a school figure in which a skater traces a large half circle, a small oval within its arc, and another large half circle to complete the figure while remaining on the same skating edge.

14.

the Loop, the main business district of Chicago.

verb (used with object)

15.

to form into a loop.

16.

to make a loop in.

17.

to enfold or encircle in or with something arranged in a loop.

18.

to fasten by forming into a loop, or by means of something formed into a loop (often followed by up):

to loop up the new draperies.

19.

to cause (a missile or projectile) to trace a looping or looplike trajectory through the air:

to loop a grenade into the building.

20.

to fly (an airplane) in a loop or series of loops.

21.

to construct a closed electric or magnetic circuit.

22.

Movies. to complete by means of looping:

We still have to loop the final scenes.

verb (used without object)

23.

to make or form a loop:

The river loops around the two counties.

24.

to move by forming loops, as a measuringworm.

25.

to trace a looping or looplike path through the air:

The fly ball looped high in the air.

26.

to perform a loop or series of loops in an airplane.

27.

Movies. to record dialogue, sound effects, etc., onto an existing film track or soundtrack.

Idioms

28.

in / out of the loop, included in or excluded from a group of people who receive the latest information about something:

"to form a loop," c.1400, "draw (a leash through a ring)," from loop (n.). Related: Looped; looping. Slang looped "drunk" is from 1934. Loop the loop (1900) originally was in reference to roller-coasters at amusement parks.

"Loop-the-Loop" is the name of a new entertainment which goes further in the way of tempting Providence than anything yet invented. The "Loop" is an immense circle of track in the air. A car on a mimic railway shoots down a very steep incline, and is impelled around the inner side of this loop. ... The authorities at Coney Island are said to have prohibited "looping-the-loop" because women break their corset strings in their efforts to catch their breath as they sweep down the incline, and moreover, a young man is reported to have ruptured a blood vessel in his liver. ["Philadelphia Medical Journal," Aug. 10, 1901]